I imagine a lot of the heavy grinding was done on very course round stones that were rigged up to a hand crank or foot pedal. I've got a small one designed for use sharpening working/kitchen knives that has a built in water trough. And there were certainly larger examples for when larger quantities of metal needed removal. My grandparents had 2 of these wheels stationed outside their house for decoration, I would say they were close to a half meter in diameter.

Smaller stones like the ones we're putting to use for our straight razors would've been used for the same purpose they are now - refreshing a dull edge on a more or less properly shaped blade. I don't think anyone would've done a lot of heavy shaping on a stationary Washita unless that was all they had.

Another factor is a small quantity of oil will last a long time. It doesn't evaporate as readily, and in areas where water would've been a bit of a rare commodity - found only in town wells out west for example - it would've made sense to keep a half pint of whale oil or similar for honing, rather than wasting any of the day/week's water ration on a sharpening stone.

I also wonder about oil vs water removing the same amount of stone over the course of it's life - at least with respect to Arkansas stones. There's an appreciable difference in how fast they burnish with water VS oil. I can count the number of razors I sharpened with water before I noticed the stones visually glazing and slowing up, this has not happened with the ones I've been using with oil (I'm actually hoping the small translucent Arkie will burnish as that would be beneficial for a finishing stone). They're also surprisingly homogenous, %99.9 silica. It's not the usual sedimentary rock that you see used as a hone most anywhere else.

I figure it's the same as using a cutting oil on a hard carbide bit used for metal. If you go after it dry or with a poor lubricant sure it'll cut, but you'll be lucky to finish one pass before the bit is dulled and in need of replacement. But with a proper lubricant you'll get the full service life out of it. It's just a lot easier to knock the burnish off a silicate stone than to sharpen a hard carbide bit - believe me, you're better off replacing the bit. I've tried. Even Arkies have nothing on those.